Lubricant composition



3,146,201 LUBRICANT COMPOSITION Thomas A. Butler, Cleveland, Ohio,assignor to The Luhrizol Corporation, Wicirlifie, Ghio, a corporation ofOhio No Drawing. Filed July 22, 1960, Ser. No. 44,559 8 Claims. (Cl.252-325) This invention relates to lubricant compositions and in a moreparticular sense to mineral oil compositions having improved resistanceto deterioration under service conditions. The lubricant compositionsare useful internal combustion engines, especially engines of the dieseltype.

The problem of deterioration of lubricating oil and formation of harmfuldeposits under service conditions has been the cause of much concern inproviding satisfactory lubrication of internal combustion engines. Theproblem is especially acute in lubricating engines of the diesel typeWhere the lubricant encounters temperatures above 700 F. and pressuresabove 1200 pounds per square inch. In recent years, it has been commonpractice to incorporate into a lubricating oil detergent additives whichare capable of preventing the deposition of the products of oildegradation. Such additives include the metal salts of sulfonic acids,carboxylic acids and organic phosphorus acids. The basic metal salts,i.e., those in which the metal is present in stoichiometrically greateramounts than the organic acid radical, are especially elfective for thispurpose. Unfortunately, however, these metal detergents tend to promoteoxidation of the oil. Thus, while lubricant compositions containing suchadditives are improved with respect to their detergent properties, theyare usually also characterized by a marked susceptibility to oxidativedegradation.

Accordingly, it is an object of this invention to provide a means forreducing the oxidation tendencies of lubricant compositions havingincorporated therein metalcontaining detergent additives.

It is also an object of this invention to provide lubricant compositionsadapted for use in internal combustion engines.

It is further an object of this invention to provide lubricantcompositions adapted especially for use in diesel engines.

These and other objects are achieved in accordance with this inventionby a lubricating composition comprising a major proportion of a minerallubricating oil, from about 0.1% to about 20% of an alkaline earth metalsalt of an acidic composition selected from the class consisting ofsulfonic acids and phosphorus acids derived from the reaction of asubstantially aliphatic hydrocarbon with an inorganic phosphorusreagent, and a small amount, sufficient to increase the resistance todeterioration of said lubricating composition due to the presencetherein of said alkaline earth metal salt, of anthranilic acid.

The amount of the detergent additive to be used in a lubricantcomposition of this invention will depend primarily upon the degree ofdetergency desired in the lubricant composition and the type of serviceto which the lubricant composition is to be subjected. For example, alubricant for use in a gasoline engine of a passenger automobile maycontain from 0.5% to 5% by weight of a detergent additive, whereas alubricant for use in a diesel engine may contain as much as or more of adetergent additive. In other applications such as in two-cycle outboardmotor type engines, a lubricant may contain only 0.1% or even less of adetergent additive.

The anthranilic acid is used in the lubricant compositions of thisinvention to reduce the oxidation-promoting tendencies of the metaldetergent additive. Hence, the amount of anthranilic acid to be useddepends to a large extent upon the amount and the type of the detergentadditive used. A small amount of a detergent additive will usuallyrequire a correspondingly small amount of anthranilic acid. In mostinstances, from 0.01% to 0.5%, more often in the neighborhood of0.02%0.2%, by weight of anthranilic acid in a final lubricant willsuffice to counteract the oxidation tendencies of a lubarium arepreferred for reasons of the particular eifectiveness of their salts asdetergent additives in the lubricant compositions of this invention.

The sulfonic acids from which the detergent additives of this inventionare derived may be either petroleum sulfonic acids (e.g., mahoganyacids) or alkylaryl sulfonic acids prepared by the treatment ofalkylated aromatic compounds with a sulfonating agent such as sulfurtrioxide, chlorosulfonic acid, sulfuric acid or the like.

The organic radical of the sulfonic acid should contain at least about12 aliphatic carbon atoms in order to impart oil-solubility.

The organic phosphorus acids from which the detergent additives arederived are principally those prepared by the treatment of a polymer ofa lower mono-olefin such as ethylene, propene, isobutene or l-butenewith a phosphorizing agent such as phosphorus pentasulfide, phosphorusheptasulfide, phosphorus sesquisulfide, phosphorus trichloride,phosphorus trichloride and sulfur, elemental phosphorus and a sulfurchloride, phosphorothioic chloride, etc. They may be prepared bychlorinating an olefin polymer and treating the chlorinated polymer witha phosphorizing agent. The phosphorized polymer may be hydrolyzed firstbefore conversion to the metal salts. Interpolymers of theabove-illustrated lower mono-olefins, aromatic olefins or diolefinslikewise are useful for preparing the organic phosphorus acids providedthat at least about 95% by weight of the interpolymer is composed of thelower mono-olefin units. Examples of the olefin polymers includepolyisobutenes, polypropenes, polyethylenes, copolymer of of isobuteneand 10% of styrene, copolymer of 98% of isobutene and 2% of chloroprene,copolymer of 99% of propene and 1% of piperylene, terpolymer of 98% ofisobutene, 1% of butadiene and 1% of n-hexene, etc. Polymers ofisobutene are most frequently used because of their ready availability.The molecular weights of the polymers may vary within wide ranges suchas, for example, from 200 to 100,000 or even higher. Polymers ofintermediate molecular weights, i.e., 50010,000 are especially useful.

As noted above the phosphorus acids are prepared from a substantiallyaliphatic hydrocarbon, i.e., one which may contain only incidentalproportions of aromaticity and only such substituents as do notmaterially alfect the aliphatic character of the molecule.

The alkaline earth metal salts of sulfonic acids and organic phosphorusacids may be neutral or basic salts obtained by treatment of the acidwith at least a stoichiometric amount of an alkaline earth metalneutralizing Patented Aug. 25, 1964 agent such as the metal oxide, metalhydroxide, metal carbonate, metal alcoholate, metal phenate, etc. Theterm basic metal salts is used to designate the metal salts of organicacids wherein the metal is present in a larger amount than isstoichiometrically equivalent to the organic acid radical. Examples ofsuch metal salts include those prepared by the processes described in USPatents 2,616,905, 2,723,234, 2,921,901, 2,902,105, 2,906,709,2,902,448, 2,865,956, 2,861,272, 2,316,080, and 2,316,081.

The most commonly employed methods for preparing the basic metal saltsinvolve heating a mixture of an acid with a stoichiometric excess of analkaline earth metal neutralizing agent at a temperature above about 50C. and filtering the reaction mass in a diluent such as mineral oil toobtain a fluid product. The use of a fpromoter in the neutralizationstep to aid the incorporation of a large excess amount of metal islikewise known. Examples of such promoter compounds include phenolicsubstances such as phenol, naphthol, alkyl phenol, thiophenol,sulfurized phenol and condensation products of formaldehyde and aphenol; alcohols such as methanol, 2-propanol, octyl alcohol,Cellosolve, carbitol, ethylene glycol, stearyl alcohol, cyclohexyalcohol; amines such as aniline, phenylenediamine, phenothiazine,phenyl-{3- naphthylamine, dodecyl amine, etc. A particularly efiicientmethod comprises mixing an acid with an excess of a neutralizing agent,a promoter compound and a small amount of water, and carbonating themixture at an elevated temperature, e.g., 60-150 C.

The present invention also contemplates the use of a corrosion inhibitorin conjunction with anthranilic acid and the detergent additive in alubricant composition. Corrosion inhibitors particularly efiective foruse in the lubricant compositions of this invention include the oilsoluble alkaline earth metal salts of alkylated phenolic compounds suchas, e.g., alkyl phenols, alkyl naphthols, sulfurized alkyl phenols ornaphthols and condensation products of such phenolic compound withaldehydes or ketones. The alkyl radical in the phenolic compound shouldcontain at least 7 carbon atoms in order to impart oil-solubility.Specific examples of such corrosion inhibitors include: barium salt ofcetyl phenol, calcium salt of otcyl phenol, strontium salt of heptylphenol, barium salt of bis-(hydroxyphenyl) sulfide, calcium salt of thecondensation product of heptyl phenol with 0.5 mole of formaldehyde,calcium salt of his (hydroxylphenyl) di-sulfide, etc. Likewise usefulare the basic alkaline earth metal salts of the alkylated phenoliccompounds wherein the metal is present in stoichiometrically largeramounts than the phenolic radical. The basic salts may be prepared byheating a mixture of a phenolic compound with an excess of an alkalineearth metal neutralization agent, or treating such mixture with carbonan elevated temperature, e.g., 60l50 C.

Another class of corrosion inhibitors contemplated for use in thelubricant compositions of this invention are the metal salts of organicphosphorodithioic acids, especially the zinc and barium salts of dialkylphosphorodithioic and dialkaryl phosphorodithioic acids. Such acids arepreferably those in which the total number of the carbon atoms in thetwo alkyl radicals is at least about 7.6 per each phosphorus atom. Themetal salts of such acids may be illustrated by e.g., zinc dipentylphosphorodithioate, zinc dicyclohexyl phosphorodithioate, bariumdi(pheptylphenyl) phosphorodithioate, barium salt of propylhexylphosphorodithioic acid, zinc salt of heptyl cresylphosphorodithioic acid, etc.

Still another class of corrosion inhibitors includes the sulfurized orphosphosulfurized hydrocarbons or fatty materials such as the reactionproducts of a-pinene with sulfur or phosphorus pentasulfide, thereaction products of methyl oleate with phosphorus sesquisulfide, thereaction products of sperm oil with sulfur, dibutyl tetrasulfide,dipentyl trisulfide, etc.

Other corrosion inhibitors are the metal salts of organic thiocarbamicacids such as zinc diheptylphenyl dithiocarbamate, zinc dipentyldithiocarbamate, cadmium cyclohexyl thiocarbamate, etc.

Yet another class of corrosion inhibitors consists of organicphosphites, especially diaryland dialkyl phosphites having the formula,(RO) P(O)H, wherein R is an aryl or an alkyl radical containing 4-30carbon atoms. They may be prepared by the reaction of an alcohol orphenol or a mixture of alcohols or phenols with phosphorus trichloride.Examples of such phosphites include: dicyclohexyl phosphite,di(4-methyl-2-pentyl) phosphite, propyl octyl phosphite,methylcyclohexylpentyl phosphite, diphenyl phosphite, etc. Otherphosphites such as triphenyl phosphite, tributyl phosphite, and hexyldicresyl phosphite are likewise contemplated.

While any of the afore-mentioned corrosion inhibitors may be used, theparticular combination of an alkaline earth metal salt of an alkylatedphenolic compound with anthranilic acid and a metal detergent has beenfound to produce lubricants which show unexpectedly high resistance tooxidative degradation. Accordingly, such combination is preferred foruse in preparing lubricants of this invention.

The amount of the corrosion inhibitor to be used in the lubricantcompositions of this invention may be varied within the range of fromabout 0.1% to about 5% by weight, more often within the range of fromabout 1% to about 3% by weight.

The use in the lubricant compositions of this invention of other typesof additives such as anti-foam agents, rust-inhibitors, pour point andviscosity index improving agents, etc. is likewise contemplated.

The following examples illustrate more specifically the additives usefulin the lubricant compositions of this invention. All parts are byweight.

EXAMPLE A Neutral Calcium Detergent Additive A mineral oil solutioncontaining 50% by weight of a sodium petroleum sulfonate (molecularweight 500) is heated at C. for 2 hours with a 20% stoichiometricallyexcessive amount of calcium chloride and 10% by weight of water. Themixture is then dehydrated by heating to 150 C. and the inorganicchlorides removed by filtration. The filtrate is an oil solution of aneutral calcium petroleum sulfonate.

EXAMPLE B Basic Calcium Detergent Additive A mixture of 520 parts of amineral oil, 480 parts of a sodium petroleum sulfonate (molecular weightof 480) and 84 parts of water is heated at C. for 4 hours. The mixtureis then heated with 88 parts of a 76% aqueous solution of calciumchloride and 72 parts of lime (90% purity) at 100 C. for 2 hours,dehydrated by heating to a water content of less than 0.5%, cooled to 50C., mixed with parts of methyl alcohol and blown with carbon dioxide at50 C. until substantially neutral. The mixture is then heated to C. todistill otf methyl alcohol and water and the resulting oil solution ofthe basic calcium sulfonate filtered. The filtrate is found to have asulfate ash of 16%.

EXAMPLE C Basic Calcium Detergent Additive A mixture of 300 grams ofmineral oil, 690 grams (0.5 mole) of neutral calcium mahogany sulfonate,75 grams of water and 29 grams of lime (90% purity) is heated at 100 C.for 2 hours and then to 150 C. during a period of 7 hours. The mixtureis blown with carbon dioxide at 150 C. until substantially neutral andfiltered. The filtrate is found to have a sulfate ash content of 8.2%.

EXAMPLE D Basic Calcium Detergent Additive A mixture of 500 parts of amineral oil, 500 parts of a neutral sodium petroleum sulfonate(molecular weight of 500), 67 parts of calcium chloride and 76 parts ofwater is heated at 100 C. for 4 hours and then mixed with 25.5 parts oflime (90% purity) at 100 C. for 2 hours. The mixture is then dried to150 C. over a period of 7.5 hours and filtered. The filtrate is found tohave a sulfate ash content of EXAMPLE E Basic Barium Detergent AdditiveA mixture of 490 parts of a mineral oil, 110 parts of water, 61 parts ofheptylphenol, 340 parts of neutral barium, mahogany sulfonate and 227parts of barium oxide is heated at 100 C. for 0.5 hour and then to 150C. Carbon dioxide is then bubbled into the mixture until the mixture issubstantially neutral. The mixture is filtered and the filtrate found tohave a sulfate ash content of 25%.

EXAMPLE F Basic Barium Detergent Additive To 900 parts of a chlorinatedpolyisobutene having a chlorine content of 4.3% and a molecular Weightof 1000 there is added 150 parts of phosphorus trichloride at 110190 C.during a period of hours. The mixture is heated at 200 C. for 2 hours,at 180190 C./ 660 mm. for 1.5 hours, and then blown with nitrogen at 170C. for 2 hours. The residue is hydrolyzed with steam to form an acidicintermediate. A basic barium salt is prepared by adding 400 parts of theacidic intermediate to a mixture of 495 parts of a mineral oil, 100parts of heptylphenol, 38 parts of Water and 62 parts of barium oxide at9095 C. during 1.5 hours. The mixture is heated at this temperature for0.5 hour, mixed with 257 parts of barium oxide and carbonated at 130-140 C. until it is substantially neutral. The resulting mixture isdiluted with 280 parts of mineral oil and filtered. The filtrate isfound to have a sulfate ash content of 25%. 1

EXAMPLE G Neutral Barium Detergent Additive A polypropene having amolecular weight of 2000 is mixed'with 10% by weight of phosphoruspentasulfide at 190 C. for 6 hours. The resulting phosphosulfurizedpolypropene is hydrolyzed by treatment with steam at 160 C. to producean acidic intermediate which is then converted to the neutral bariumsalt by treatment with a stoichiometric amount of barium hydroxide.

EXAMPLE H Basic Magnesium Detergent Additive A methyl alcohol suspensioncontaining 14% by weight of suspended magnesium methoxide is blown withcarbon dioxide at 40 C. until it is acidic to a-naphtholbenzeinindicator, whereupon a homogeneous solution is obtained. The solution(200 parts by weight) is added dropwise to 27 parts of an alkylatedbenzenesulfonic acid having a molecular weight of 450, 123 parts of amineral oil and 75 parts of water, and the resulting mixture is heatedto 150 C. The residue is filtered and the filtrate contains 40% byweight of sulfate ash.

EXAMPLE I Neutral Strontium Detergent Additive A copolymer of isobuteneand styrene (molar ratio of 10.5 :1 respectively) having a molecularweight of 1000 is heated with 8.6% by weight of sulfur to 200 C.whereupon 37% by weight of phosphorus trichloride is added to themixture at 170-200 C. during a period of 6 5 hours. The mixture is thensubjected to distillation at 170 C./50 mm. for 1 hour, and the residuediluted with 44% by weight of a mineral oil. The oil solution is foundto contain 3% of phosphorus, 4.7% of sulfur, and 2.7% of chlorine. Steamis passed into the oil solution to produce an acidic intermediate whichis then treated with a stoichiometric amount of strontium hydroxide toproduce a neutral strontium salt of an organic phosphorus acid.

EXAMPLE I Neutral Barium Detergent Additive To 4400 grams of a mineraloil solution containing 4.25 moles of sodium mahogany sulfonate there isadded 680 grams of barium chloride dihydrate in 1500 ml. of water at 95C. The mixture is heated at 90 C. for 1.5 hours, and the aqueous layerremoved. The oil layer is washed with water-isopropanol-phosphoric acidmixture, then dried at 160 C./30 mm. and filtered. The filtrate has asulfate ash content of 10.7%.

EXAMPLE K Basic Strontium Detergent Additive A mixture of 910 grams of amineral oil solution containing 0.9 equivalent of strontium mahoganysulfonate,

80 grams of strontium hydroxide octahydrate and 145- grams of water isheated at 93-99 C. for 2 hours, then heated to 150 C. in 7 hours, andfiltered. The filtrate has a sulfate ash content of 14.2%.

EXAMPLE L Basic Barium Detergent Additive A mixture of 900 grams of amineral solution containing 0.41 mole of barium mahogany sulfonate, 46grams of barium oxide, 145 grams of water and 64 grams of mineral oil isheated at 93 99 C. for 2 hours, then heated to 150 C. in 7 hours, andfiltered. The filtrate has a sulfate content of 15:6

EXAMPLE M Neutral Calcium Detergent Additive To 6500 grams of a mineraloil solution containing 6.53 moles of sodium mahogany sulfonate there isadded at 95% C. 622 grams of calcium chloride dihydrate in 1800 ml. ofwater. The mixture is heated at 95-100 C. for 0.5 hour and allowed tosettle at room temperature for 2 days. The aqueous layer is removed, andthe oil layer is Washed with water and then with aWater-isopropanolphosphoric acid mixture. The washed layer is dried andfiltered. The filtrate has a sulfate ash of 6.9%.

EXAMPLE N Basic Barium Detergent Additive To a mixture of 1000 parts ofa chlorinated polyisobutene having a chlorine content of 4.3% and amolecular weight of 1000 and parts of phosphorus trichloride, there isadded portionwise throughout a period of .5 hour 61 parts ofheptylphenol at 210 F. The mixture is heated to 390 F. whereupon anadditional 1'10 parts of phosphorus trichloride is added throughout aperiod of 6 hours. The mixture is heated at 390 F. for 0.5 hour, blownwith nitrogen at 360390 F./ 100 mm. for 2 hours, and then with steam at300-320 F. for 3 hours. To a mixture of 270 parts of mineral oil, 18parts of water and 15 parts of barium oxide, there are added 143 partsof the above steam-hydrolyzed product and 38 parts of heptylphenol at190 -195 F., and then 125 parts of barium oxide at 200230 F. The mixtureis heated to 270-280 F. and blown with carbon dioxide untilsubstantially neutral. The mixture is heated to 270- 280 F and blownwith carbon dioxide until substantially neutral. The residue is dilutedwith parts of mineral oil, blown with nitrogen at 310 F. for 0.5 hour,and filtered. The filtrate has a sulfate ash content of 25 7 EXAMPLEBasic Barium Detergent A dd i ti ve To a mixture of 6,245 grams (12.5equivalents) of barium petroleum sulfonate, 1,460 grams (7.5equivalents) of heptyl phenol and 2,100 grams of water in 8,045 grams ofmineral oil there is added at 180 F. 7,400 grams (96.5 equivalents) ofbarium oxide. The addition of barium oxide causes the temperature torise to 290 F. and this temperature is maintained until all of the waterhas been distilled away. The mixture then is blown with carbon dioxideuntil it is substantially neutral. 5,695 grams of mineral oil is addedand the mixture filtered through a siliceous filter aid. The filtrate isdiluted further with mineral oil to a barium content of 38.5% as sulfateash.

EXAMPLE P Basic Calcium Detergent Additive Same as additive B exceptthat sodium polydodecylbenzene sulfonate is used in the place of sodiummahogany sulfonate.

EXAMPLE Q Calcium Phenolic Corrosion Inhibitor A mineral oil solutioncontaining 50% of cetyl phenol is heated with a stoichiometric amount ofcalcium oxide and 10% by weight of water at 150-170 C. for 8 hours. Themixture is then dried at 150 C./l mm. pressure.

EXAMPLE R Calcium Phenolic Corrosion Inhibitor A mixture of 315 parts ofmineral oil, 125 parts of heptylphenol and 26.4 parts of lime is heatedat 105 108 F. for minutes and to this mixture there is then added 5.8parts of aqueous ammonium hydroxide and 29.3 parts of paraformaldehydeat 115-120 F. The mixture is maintained at 155-180 F. for 1 hour andthen heated to 300 F. in 5 hours whereupon the water is removed bydistillation. The residue is dried by heating at 300305 F. for 1 hour,mixed with 18 parts of a filter aid and filtered. The filtrate has asulfate ash content of 6.2.

EXAMPLE S Calcium Phenolic Corrosion Inhibitor A mineral oil solutioncontaining 50% by weight of a mixture of stoichiometrically equivalentamounts of his (heptylphenyl) sulfide and hydrated lime is heated at 200C. for 6 hours and filtered. The filtrate is the neutral calcium salt.

EXAMPLE T Barium Phenolic Corrosion Inhibitor A mixture of 400 grams ofheptylphenol, 54 grams of water, 1150 grams of mineral oil and 163 gramsof barium oxide is heated at 160l70 C. for 2 hours and filtered. Thefiltrate has a barium content of 4.8%.

EXAMPLE U Magnesium Phenolic Corrosion Inhibitor A mineral oil solutioncontaining 40% by weight of dipentylphenol is mixed with a 20%stoichiometric excess of magnesium methoxide suspended in methylalcohol. The mixture is heated at reflux temperature for hours and thendistilled to remove any volatile components. The residue is filtered toyield as the filtrate an oil solution of the magnesium salt.

EXAMPLE V Barium Phenolic Corrosion Inhibitor A mixture of 309 grams(1.5 equivalents) of octylphenol, 1500 grams of mineral oil, 344 grams(4.5 equivalents) of barium oxide and 180 grams (10 equivalents) ofwater is stirred at reflux temperature for an hour, then heated to 150C. and held at 150-160 C. for an hour. Carbon dioxide is bubbled intothe mixture for 35 minutes at 150 C. and the hot mixture is filtered.The filtrate has the following analysis: percent sulfate ash, 21.2;neutralization No. 16.7 (basic).

EXAMPLE W Zinc Phosphorodithioate Corrosion Inhibitor Aphosphorodithioic acid prepared by the reaction of phosphoruspentasulfide with four moles of an equimolar mixture of sec-butylalcohol and cyclohexyl alcohol is neutralized by treatment with a 20%stoichiometric excess of zinc oxide at C. The resulting zincphosphorodithioate is filtered.

EXAMPLE X Phosphosulfurized Cyclic Hydrocarbon Corrosion Inhibitor Asolution of 250 grams of pinene in 250 grams of mineral oil is heatedwith grams of phosphorus pentasulfide at 150 C. for 2 hours. The mixtureis filtered and the filtrate has a phosphorus content of 4.8% and asulfur content of 13%.

The following examples illustrate the lubricant composition of thisinvention.

Lubricant 1: Parts SAE 20 mineral oil 100 Anthranilic acid 0.02 Calciumdetergent additive of Example A 6 Lubricant II:

SAE low-30 mineral oil 100 Anthranilic acid 0.05 Basic calcium detergentadditive of Example D 10 Lubricant III:

SAE 30 mineral oil 100 Anthranilic acid 0.3 Basic barium detergentadditive of Example E- 15 Calcium phenolic corrosion inhibitor ofExample Q 3 Lubricant IV:

SAE 40 mineral oil 100 Anthranilic acid 0.075 Neutral barium detergentadditive of Example G 3 Phosphosulfurized cyclic hydrocarbon corrosioninhibitor of Example X 2 Lubricant V:

SAE mineral oil 100 Anthranilic acid 0.1 Basic calcium detergentadditive of Example D 10 Calcium phenolic corrosion inhibitor of ExampleR 2 Polyalkylsiloxane anti-foam agent 0.003 Polyalkylmethacrylateviscosity index improving agent 1.5 Alkenylsuccinic acid rust-inhibitor0.05

Lubricant VI:

SAE 30 mineral oil 100 Anthranilic acid 0.01

Basic magnesium detergent additive of Example H 1 Calcium phenoliccorrosion inhibitor of Example S 0.5 Lubricant VII:

SAE 30 mineral oil 100 Anthranilic acid 0.05 Neutral strontium detergentadditive of Exarnple I 3 Zinc phosphorodithioate corrosion inhibitor ofExample W 1 9 10 Lubricant VIII: Parts as well as many other within thebroad definition of the SAE 30 Mineral oil 100 combination of theinvention. Anthranilic acid The oxidation resistance of the lubricantsof this in- Bas c barium de e g addltlve of Example 6 vention is shownby the results of the Air Oxidation Test Basiccalcmm det g Q l P 7summarized in Table I. The test consists of bubbling Phenohc corroslonmhlbltor of Exam 2 5 air at the rate of 1 cubic foot per hour into 300grams "ttjf 0 6 of a lubricant having immersed therein a sheet of copya(y 51 Oxane an 0am agen per (2 x 8 x 0.33 inches) as an oxidationpromoter at Lubricant IX: I 100 300i5 F., and measuring the viscosityincrease of the i gf q id 0 O3 10 l ricant at 24 hour intervals until asharp increase in E i 5 33 g &;-- viscosity occurs. The results areexpressed in terms of 1e ge a 1 e 4 percent of viscosity increase. Itwill be readily. appreci- Bagium g g g g gg ated that a smaller increasein viscosity indicates a greater ple V 1 r resistance to oxidativedegradation of the lubricant. The LubricantX lubricant used in the testsconsists of an SAE 30 grade SAE 3 mineral oil 100 oil to which has beenadded the corrosion inhibitor of EX- Anfhranih-c acid 01 ample R invarious amounts according to the following Basic barium detergentadditive of Example EL 4 scheduie: i i A cpmammg Welght Of.the Basiccalcium detergent additive of EXam corrosion mhibnor; lubricant Bcontaining 2% by weight ple B 6 of the corrosion inhibitor; andlubricant C containing 3% Polyalkyl acrylate viscosity index improving yWelght Of the b tor.

agent 2 It has been found also that lubricant compositions Polyalkylacrylate anti-foam agent 0 .005 taining a mixture of barium and calciumdetergent addi- Calcium phenolic corrosion inhibitor of Examtives inweight proportions within the range of from about P S 3 5:1 to about 1:5respectively are especially susceptible to Lubricant XI: theoxidation-retarding effects of anthranilic acid. Ordi- SAE 'f 011 narilylubricant compositions contain from about 0.1% g h g t 3: to about 10%of each of the calcium and barium deter-' 232 gfig g g g gg i gf gentadditives. These calcium and barium detergent adple B g 3 ditives, whenused in combination in the same lubricant, polybutene vigcosityimproving agent 5 most usually are sulfonates, i.e., a combination ofcalp l lk l il a ti f agent (10 03 clum sulfonate and a bar1umsulfonate. This particular Calcium phenolic corrosion inhibitor ofExamcombination is especially eifective in the presence of ple Ranthranilic acid.

TABLE I.AIR OXIDATION TEST RESULTS Anthra- Percent viscosity increase atend of test nilic Detergent additive period of Test Lubriacid 1% (1%addition by sample cent addition weight) by 72 144 166 weight) hourshours hours hours hours 1 A None 12%ofadditiveof 83 175 410 1V.V.Example 0. r 2 A 0.05 do 0 0 2 4 s 3 B None 9.4% of additive 80 V.V

of Example J 4 B 0.05 .do 0 0 41 107 133 5 B None 7% of additive of 21183 314 796 Example K. e B 0.05 do 5 5 6 7 24 7 B None 6.4% of additive31 346 V.V

of Example L. s B 0.05 ..-.do 3 3 61 159 9 0 None 10.4% of additive 16692 V.V

of Example B. 10 0 0.05 do 10 14 47 227 604 11 0 0.1. do 10 12 17 83 29212 B None 14.5% additive of 18 V.V

- Example M. 13 B 0.05 do 0 0 0 10 99 14 D 0.075 11%0fadditive of 10 1735 79 Example P.

1 V.V., very viscous, i.e., viscosity increase above 450%500%. 2 SAE oilcontaining 0.1% of Zinc dioctyl phosphorodithioic acid as corrosioninhibitor Lubricant XII. P arts Examples of such lubricant compositionsinclude min- SAE 30 mineral oil The above lubricants are of coursemerely illustrative and the scope of the invention includes the use ofall of 65 eral lubricating oils in which there are incorporated about0.0l%0.5% by weight of anthranilic acid and detergent additivecombinations such as: 1% of neutral calcium mahogany sulfonate and 5% ofneutral barium mahogany sulfonate; 5% of neutral calcium didodecybenzenesulfomate and 5% of neutral barium salt of the hydrolyzed reactionproduct of phosphorus pentasulfide with polyisobutene having an averagemolecular weight of 1000: 8% of a basic calcium salt of diodecylbenzenesulfonic acid prepared by carbonating at 6080 C. a mineral oil soluthedetergent additives and inhibitors previously illustrated 75 tion of theacid with five chemical equivalents of calcium 1 hydroxide in thepresence of methyl alcohol as the promotor, and 8% of a neutral bariumdidodecylbenzene sulfonate; of the calcium detergent of Example 2 and 2%of the barium detergent of Example 0; 3% of the calcium detergent ofExample D and 9% of the barium detergent of Example E.

The Air Oxidation Test results summarized in Table II illustrate theunusual oxidation stability of lubricant componsitions contininganthranilic acid and such a mixture of barium and calcium detergentadditives.

The calcium and barium sulfonates used in the lubricant compositionsindicated earlier as being especially preferred may be derived fromeither petroleum sulfonic acids or synthetic alkaryl sulfonic acids.Thus the barium sulfonate may be either barium mahogany or bariumalkaryl sulfonate and the calcium sulfonate likewise may be either ofthese types. Further, the combination of calcium and barium sulfonatesin one lubricant composition may include all possible combinaations ofcalcium, barium, mahogany sulfonates and synthetic alkaryl sulfonates.

What is claimed is:

1. A lubricating composition comprising a major proportion of a minerallubricating oil, from about 0.1% to about 10% of an oil-soluble calciumsalt of a sulfonic acid selected from the class consisting of petroleumsul- TABLE II.AIR OXIDATION TEST RESULTS [all percent addition byweight] An- Corro- Percent viscosity increase at end of testthrasioninperiod of- Test nilic hibitor Ca-detergent Bat-detergentsample acid of example R 72 96 120 144 166 hours hours hours hours hours1 0.05 3 10.4% ofadditive None 10 14 47 227 601 of Example B. 2 0.05 3None 12% ofadditive 9 79 215 484 of Example E. 3 0.05 2.5 5.8%ofadditive 5.4% ofadditive 7 10 13 15 17 of Example 13. of Example E. 40. 075 2 8.2% ofadditive 3% oiadditive 12 10 21 27 125 of Example 13. ofExample E. 5 0.05 3 10.4% oiadditive None 10 14 47 227 004 of Example B.6 0.05 3 None 12% of additive 11 23 107 232 451 of Example F. 7 0.05 34.50% of additive 4.44% ofadditive 9 12 10 16 of Example B. of ExampleF. s 0. 05 3 7% of additive of 4% ofadditive 9 10 11 14 10 Example B. ofExample N 9 0.075 2 5.8% ofadditive 5.2% ofadditive 7 s 11 13 18 ofExample B. of Example N. 10 0. 075 2 8.2% ofadditive 3% of additive 9 1317 21 32 of Example B. of Example N. 11 0.05 3 None 11.5 ofadditive 8 55226 500 of Example 0. 12 0.05 3 10.4% of additive None 12 207 566 ofExample P. 13 0.05 3 5.6% of additive 5.75% oi additive 13 1s 1s 47 217of Example I. of Example 0. 14 0.025 2 9.8% oi additive 2.28% oiadditivc13 14 1s 22 23 of Example B. of Example 0.

Lubricant XIII: Parts fonic acids and alkaryl sulfonic acids; from about0.1% SAE 30 mineral oil 100 to about 10% of an oil-soluble barium saltof an acid Anthranilic acid 0. selected from the class consisting ofpetroleum sul- Basic barium sulfonate of Example O (but prefonic acids,alkaryl sulfonic acids, and phosphorus acids pared from polydodecylbenzene sulfomc acid 50 obtained by reacting a polymer selected from theclass instead of petroleum sulfonic acid) 8 consisting of isobutenepolymers and chlorinated iso- Basic calcium sulfonate of Example B 2butene polymers having a molecular weight from about Zinc dihexylphosphorodithioate 1 200 to 100,000 with a phosphorus reagent selectedfrom Lubricant XIV: the class consisting of phosphorus trichloride andphos- SAE 30 mineral oil 100 phorus pentasulfide; and a small amount,suflicient to in- Anthranilic acid 0.3 crease the resistance todeterioration of said lubricating Basic barium sulfonate of Example 0(but precompositions due to the presence therein of said calcium paredfrom polydodecyl benzene sulfonic acid and barium salts, of anthranilicacid.

instead of petroleum sulfonic acid) 6 2. A lubricating compositioncomprising a major pro- Basic calcium sulfonate of Example P 1.5 portionof a mineral lubricating oil, from about 0.1% to Zinc isopropyl hexylphosphorodithioate 1 about 10% of an oil-soluble, basic calcium salt ofan Lubricant XV: alkaryl sulfonic acid; from about 0.1% to about 10% ofSAE 30 mineral oil 100 an oil-soluble, basic barium salt of a phosphorusacid ob- Anthranilio acid 0.3 tained by reacting a chlorinatedpolyisobutene having a Basic barium sulfonate of Example E (butpremolecular weight from about 500 to about 10,000 with pared from a50-50 mixture of mahogany and phosphorus trichloride; and a smallamount, sufficient to polydodecyl benzene sulfonates) 5 increase theresistance to deterioration of said lubricat- Basic calcium sulfonate ofExample P 3 ing composition due to the presence therein of said calci-Calcium phenolic corrosion inhibitor of Exum and barium salts, ofanthranilic acid.

ample Q 2 3. A lubricating composition comprising a major proportion ofa mineral lubricating oil, from about 0.1% to about 10% of anoil-soluble, basic calcium salt of an alkaryl sulfonic acid; from about0.1% to about 10% of an oil-soluble, basic barium salt of a phosphorusacid obtained by reacting a polyisobutene having a molecular Weight fromabout 500 to about 10,000 with phosphorus pentasulfide; and a smallamount, suflicient to increase the resistance to deterioration of saidlubricating composition due to the presence therein of said calcium andbarium salts, of anthranilic acid.

4. A lubricating composition comprising a major proportion of a minerallubricating oil, from about 0.1% to about 10% of an oil soluble calciumsalt of an acid selected from the class consisting of petroleum sulfonicacids and alkaryl sulfonic acids, from about 0.1% to about 10% of an oilsoluble barium salt of an acid selected from the class consisting ofpetroleum sulfonic acids and alkaryl sulfonic acids, and a small amount,sufiicient to increase the resistance to deterioration of saidlubricating compositions due to the presence therein of said calcium andbarium sulfonates, of anthranilic acid.

5. The lubricating composition of claim 4 characterized further in thatthe calcium sulfonate and barium sulfonate are each derived from amahogany acid.

6. The lubricating composition of claim 4 characterized further in thatthe calcium sulfonate and barium sulfonate each containstoichiometrically excessive amounts of metal.

7. The lubricating composition of claim 4 characterized further in thatit contains from about 0.01% to about 5.0% of a calcium salt of an alkylphenol-formaldehyde condensation product.

8. The lubricating composition of claim 4 characterized further in thatthe calcium sulfonate and barium sulfonate are each carbonated basicmetal sulfonates.

References Cited in the file of this patent UNITED STATES PATENTS1,975,755 Hoyt et a1. Oct. 2, 1934 2,151,300 Moran et al Mar. 21, 19392,3 69,090 Trautman Feb. 6, 1945 2,390,943 Kavanagh et a1 Dec. 11, 19452,629,693 Barton et a1 Feb. 24, 1953 2,723,234 Asefr' et al Nov. 8, 19552,736,701 Nefi Feb. 28, 1956 2,815,370 Hutchings et a1 Dec. 3, 19572,844,535 Blumer July 22, 1958 2,846,466 Crosby et a1 Aug. 5, 19582,849,398 Moody et a1 Aug. 26, 1958 OTHER REFERENCES Georgi: Motor Oilsand Engine Lubrication, 1950, Reinhold Publishing Corporation, pages170190 pertinent.

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERALLUBRICATING OIL, FROM ABOUT 0.1% TO ABOUT 10% OF AN OIL-SOLUBLE CALCIUMSALT OF A SULFONIC ACID SELECTED FROM THE CLASS CONSISTING OF PETROLEUMSULFONIC ACIDS AND ALKARYL SULFONIC ACIDS; FROM ABOUT 0.1% TO ABOUT 10%OF AN OIL-SOLUBLE BARIUM SALT OF AN ACID SELECTED FROM THE CLASSCONSISTING OF PETROLEUM SULFONIC ACIDS, ALKARYL SULFONIC ACIDS, ANDPHOSPHORUS ACIDS OBTAINED BY REACTING A POLYMER SELECTED FROM THE CLASSCONSISTING OF ISOBUTENE POLYMERS AND CHLORINATED ISOBUTENE POLYMERSHAVING A MOLECULAR WEIGHT FROM ABOUT 200 TO 100,000 WITH A PHOSPHORUSREAGENT SELECTED FROM THE CLASS CONSISTING OF PHOSPHORUS TRICHLORIDE ANDPHOSPHORUS PENTASULFIDE; AND A SMALL AMOUNT, SUFFICIENT TO INCREASE THERESISTANCE TO DETERIORATION OF SAID LUBRICATING COMPOSITIONS DUE TO THEPRESENCE THEREIN OF SAID CALCIUM AND BARIUM SALTS, OF ANTHRANILIC ACID.